In the related art, for example, a battery pack that is configured by connecting a plurality of single cell groups in parallel is known. The single cell group is configured by connecting a plurality of single cells in series. In addition, a fuse is provided in each single cell group, and when an abnormality such as internal short-circuit occurs in a single cell, by melting and cutting the fuse of the single cell group including the single cell in which the abnormality has occurred, only the single cell group in the abnormal state is opened and connection of the to a load is cut off (refer to Patent Document 1).